Method for making rigid structures from panels

ABSTRACT

The invention concerns a method for making a three-dimensional rigid structure by wedging from at least an initial flat panel. A drill runs along and cuts the panel producing one or more rectangular recesses to obtain ladder-type frames provided with cut-out edges and side panels provided with notches. The notches and cut-out edges with rounded bases are designed to co-operate and enable a side panel to be wedged between two parallel ladder-type frames provided with a floor panel, the latter being obtained separately. The floor panel is provided with four notches designed to be wedged in the edge of four vertical posts of two ladder-type frames arranged parallel.

A method for assembling rigid structures, e.g. shelves, by wedging is known from European Patent 0 794 716, the disclosure of which is incorporated herein by reference. At least two panels, preferably cut-out panels with notches and/or grooves are wedged in at least two frames or a ladder-type frame.

This invention provides an improvement to this method, by allowing a simpler and less expensive construction.

The panels of the above patent may be made of several different materials, particularly of plastic. Wood is preferred, particularly compregnated or reconstituted wood, more particularly MDF. They are advantageously obtained by relieving the original panels, for instance by laser cutting. While this technique has been found to be particularly appropriate, it is also expensive and involves a relatively long fabrication time per structure.

Other means exist for making these panels and frames: molding, sawing, drawing, water-jet cutting. These three methods allow to pull out the cut-out panels from within the ladder-type frames (which are also cut out with the same method) and to obtain the final structure from a commercially available standard panel, in one step, and with actually no scrap (loss of material).

This invention provides a method for obtaining the same result by recessing a panel, i.e. by using a drill which rotates at high speed as it runs. The drill, for instance a diamond drill, removes a certain amount of material, depending on its diameter and on the path of the drill along the panel to be cut out or recessed.

This method is also particularly interesting in that it allows to cut out several superimposed panels in one step, at a speed equal to or higher than water-jet or laser cutting. This reduces the cutting time at least in proportion to the number of superimposed base panels. Therefore, for 3 simultaneously processed panels: ⅓ of the cutting time for each fabricated structure. The panels may be processed simultaneously, for instance by using an integration technique in which vacuum is applied on the surface of a panel.

Nevertheless, two problems arise when relieving an original panel to obtain the ladder-type frames and the cut-out panels in one step:

The cutting line is important, as it is a function of the drill thickness, i.e. the greater the drill, the more solid it is and the higher is its running speed. However, due to the thickness of the cutting line, and even when considering the thickness of the floor panel, a pseudo-square side panel (e.g. a side panel one side whereof is longer by one panel thickness) removed from the ladder with this method would be too short to be wedged between the rungs and ensure the solidity of the structure.

The cross section of the drill is obviously round, and once it has run along the square or rectangular perimeter that will allow removal of the cut-out panel with notches from the ladder, the four inner corners of the latter will be rounded, and this further prevents a panel from directly contacting the rung and the side panels from directly contacting the uprights of the ladder, to obtain the inventive structure.

According to the invention, these drawbacks are obviated by providing a method as claimed in the claim 1 hereafter, as further shown with reference to the annexed drawings.

The first of the above drawbacks is obviated as follows:

The side panels to be pulled out from the ladders are rectangles whose upper notches will be formed in one of the two smaller sides. The rectangle so released will be longer in proportion with the thickness of the cutting line, which will allow to “recover” somehow and to wedge anyway the latter between the uprights. The floor panels will be cut-out separately so that they are large enough for their four notches to hold the four uprights of the ladder-type frame.

According to the invention, the second of the above drawbacks is obviated as follows:

In order that the floor panel may be laid flat on the upper edge of the rungs, the drill is used to trim up to a certain distance, so as to remove the rounded portion, on both sides of the upright.

Preferably such trimming action will be done on the two uprights, so that the trimming marks may be hidden by the ends of the panels after assembly.

In order that the side panels may be wedged in parallel arrangement against the uprights, the drill is used to trim up to a certain distance, so as to remove the rounded portions at the intersections between the lower edges of the rungs and the inner edges of the uprights.

Preferably such trimming action will be done on both sides and on the rung, so that the trimming marks may be hidden by the upper ends of the side panels, more particularly by the notches of the side panels, after assembly.

According to the presently preferred embodiment of the invention, the trimmed portions cooperate with the notches of the panel to assemble a three-dimensional structure and ensure its rigidity by wedging.

According to one aspect of the invention, the widths of the notches are selected so that, during assembly, one notch may penetrate a corresponding trimmed portion or vice versa.

Hence, the trimmed portions may have a depth corresponding to a radius of the drill, which is sufficient to remove the round portions. The notches of the side panels will have such a depth that the distance between the bottom of the notch of the side panel and the opposite end of the panel is slightly greater than the distance between the top of the floor panel and the bottom of the upper trimmed portion in the rung, which will allow force wedging of the side panel.

It shall be noted that, in one embodiment, the floor panels with four notches have a certain clearance in said notches once they are placed between two frames, before wedging with the side panels.

Thus it should be noted that the floor panels are not necessarily wedged between the uprights. A certain clearance or horizontal flutter may occur, caused by the sizes of the trimmed portions in the uprights on both sides. During disassembly, the floor panel will be advantageously pushed into the bottom of a trimmed portion before being released and disengaged from the side of the opposite trimmed portion.

The final rigidity of the structure is essentially due to the wedging of the edges of the side panels between the floor panel and the upper uprights opposite to them. More particularly, according to the preferred embodiment, wedging of the side panel occurs between the bottoms of two notches of the side panels introduced in the trimmed parts of the rungs and the upper face of the floor panel adjacent said side panel.

It shall be further understood that the width of the notches which are designed to hold the uprights or rungs shall be equal to or slightly greater than the thickness of the panels. The drill that makes the notch, if its diameter is smaller than the thickness of the panel shall be used to enlarge the notch in a known manner.

It shall be finally noted that, by the recessing process, the notch bottoms are apparently rounded (like the drill), and this surprisingly affects neither the positioning of the ladder-type frame nor the force wedging of the side panels between the two, or more ladder-type frames with their floor panels fitted thereon.

The invention is further described in the following examples with reference to the annexed drawings, in which

FIG. 1 is a schematic view of a simple frame with a rectangular recess having four rounded corners, which shows the impossibility of properly laying the floor panels against the rungs and/or sideways against the uprights.

FIG. 2 is a plan view of a cut-out panel allowing to form a ladder-type frame having trimmed portions and three notched side panels.

FIG. 3 is a more detailed view of a simple structure, the notches and the trimmed portions being invisible after assembly.

FIG. 4 is a view of the assembly of a three-dimensional structure according to the invention, based on the ladder-type frame of FIG. 2.

In the drawings, like reference numerals designate like or equivalent elements.

In these embodiments, the panels are 9 mm thick MDF panels, possibly mass colored (“Valchromat”). A digital recessing machine is used which has a diamond drill having a diameter of 8 mm, and adjusted to make notches and trimmed portions with a thickness of at least 4 mm.

FIG. 1 is a schematic view of a simple frame (ladder-type with one recess) with a side panel 3 and a floor panel 10 arranged perpendicularly. The recess 2 has a rectangular shape and is obtained by recessing, with four rounded corners 20. As is apparent, the floor panels 10 cannot be properly laid over the lower rung 5 and the side panel 3 cannot be properly laid over the upright 6.

FIG. 2 is a plan view of a panel 1 which has been cut out to form, by a digital recessing machine, three recesses 2, to be covered by three cut-out panels 3. The panel 1 so recessed forms a ladder-type frame 4 having three layers composed of rungs (5, 5′, 5″) and lateral uprights 6, 6′. The side panels 3 have a rectangular shape, their length being equal to their width with the addition of twice the thickness of the drill line. In the example of the figures, the drill is of 8 mm, and the panel 3 is of 340×324 mm.

In order that, during the assembly described hereafter, the side panels 3 can be properly wedged against the inside of the uprights 6, a trimmed portion 7 is provided in the lower edge 55 of each end of the corresponding rung. Trimmed portions 8 are further provided in the edge 66 of the uprights at the base of each recess.

Also, the side panels have two symmetric notches 9 adapted to cooperate with the trimmed portions 7, 8.

FIG. 3 shows these notches and trimmed portions in greater detail. The notches have a depth of 9 mm and a width of 9 mm.

It shall be noted that these additional trimmed portions 7, 8 in the ladder-type frame can be formed separately or advantageously formed as the drill runs, in which case they only require a to and fro motion at certain locations. These trimmed portions have a depth of 4 mm, hence they have a semicircular profile with a radius of 4 mm.

FIG. 4 shows the assembly of a shelf according to the invention, based on the elements of FIG. 2 with the above mentioned size, and floor panels 10 with notches 11. The panel is a rectangular 370×324 mm panel with 9.5 mm wide and 9.3 mm deep notches.

Two ladder-type frames are disposed in parallel arrangement. A first floor panel is horizontally wedged at the base of the first notch, by allowing the notches 11 to cooperate with the trimmed portions 8. Then, a first side panel may be introduced obliquely, while allowing the notches 9 to correspond to the trimmed portions 7 and while forcing the side panel up until it is adjacent the upright 6 of the ladder-type frame 4. This step may be repeated with a side panel to be placed on the opposite side. A second floor panel is then added, and so on.

At the end of the assembly process, an appropriately sized ceiling panel 12 is wedged between the two opposite sides of the upper rungs and rests on the upper edge of two side panels.

It shall be noted that, once the structure has been assembled according to this preferred embodiment of the invention, the trimmed portions of the rung 7 are hidden by the notches 9 of the side panels 3 and the trimmed portions 8 of the upright 6 are hidden by the notches 11 of the floor panels 10. 

1: A method for making a three-dimensional rigid structure from at least one original flat panel, characterized in that a drill runs along and cuts the panel while forming one or more rectangular recesses to obtain a ladder-type frame having trimmed portions and side panels having notches, said notches and trimmed portions being provided to allow a side panel to be wedged between two parallel ladder-type frames with a floor panel fitted thereon, the latter being obtained separately. 2: A method as claimed in claim 1, wherein the notches and trimmed portions are provided to cooperate during wedging. 3: A method as claimed in claim 1 or 2, wherein trimmed portions are provided at the upper corners of each recess of the ladder-type frame. 4: A method as claimed in claim 1, wherein the trimmed portions are formed in the corresponding rung, parallel to the uprights. 5: A method as claimed in claim 1, including the provision of a floor panel having four notches adapted to be wedged in the edges of the four uprights of two parallel ladder-type frames. 6: A method as claimed in claim 1, wherein the floor panels are obtained by being cut out from a larger original panel with the help of a saw. 7: A method as claimed in claim 5 or 6 wherein the notches are obtained by using a drill. 8: A method as claimed in claim 1, wherein the drill forms a trimmed portion in the uprights at each lower corner of the recesses, the trimmed portions so obtained being adapted for cooperating with the notches of the floor panel. 9: A three-dimensional structure comprising at least two ladder-type frames having trimmed portions and side panels having notches, said notches and trimmed portions having round bottoms and cooperating by wedging a side panel between two parallel ladder-type frames with one floor panel fitted thereon. 10: A structure as claimed in claim 9, wherein the floor panel has at least four notches which are adapted to hold the edge of an upright. 11: A structure as claimed in claim 9 or 10 wherein the notches have rounded bottoms. 12: A structure as claimed in claim 9, wherein the trimmed portions in the uprights are formed at each lower corner of the recesses, the trimmed portions so obtained being adapted for cooperating with the floor panel. 13: A structure as claim in claim 9, wherein the side panels are wedged against the uprights of the ladder-type frames. 14: A piece of furniture comprising a structure as claimed in claim
 9. 15: A shelf comprising or formed by a structure as claimed in claim
 9. 16: An assembly of combined elements, adapted to be assembled to form a structure or a shelf as claimed in claim
 9. 